The invention relates to a fluid tank mounting assembly for a motor vehicle, and in particular to an improved assembly wherein the tank is directly and securely attached to the vehicle body without the need for intermediate brackets, while simultaneously ensuring an excellent seal between two halves of the tank.
A metal fluid tank for a motor vehicle, such as a fuel tank, is commonly comprised of two shells or halves that are joined together at a flange in a fluid-tight manner. The top half may be directly welded to the vehicle body at several sheet metal tabs. Unfortunately, this type of attachment has various disadvantages. For example, the sheet-metal tabs can bend or tear way, and their welded connection to the container is subject to corrosion.
A different approach is described in U.S. Pat. No. 4,444,373. In this disclosure, the flange has apertures for inserting screw bolts there through. Brackets or mounting members are attached to the floor panel of the vehicle, and are formed with through-apertures at positions aligned with the apertures of the flange, with nuts secured in alignment with the through-apertures. Bolts are subsequently threaded into the nuts, whereby the tank is fixedly mounted, in a suspended manner, onto the mounting members. This approach involves the welding of additional parts, namely the mounting members, which increases the manufacturing cost.
A simpler approach, involving the direct attachment of the tank flange to the vehicle body with a bolt, has been tried unsuccessfully. In practice, the seal between the two tank halves deteriorates over time at the aperture in the flange, in part due to the large distance from the edge seam to the apertures of the tank halves. In the case that the tank is a fuel tank, this sealing deterioration around the bolt aperture leads to undesirable fuel leakage or fuel vapor emissions, which is also unacceptable in light of more stringent government emission regulations.
An object of the present invention is to provide a fluid tank mounting assembly for a motor vehicle, which achieves direct attachment of the tank to the vehicle body while simultaneously ensuring an adequate seal between the two tank halves.
Other objects and advantages of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
A fluid tank assembly comprises a first tank half having an upper edge flange with an expanded section or ledge extending outwards, with the ledge having an aperture. A second mating tank half similarly has a lower edge flange and extending ledge with an aperture that is smaller in diameter than the upper aperture. The extending ledge of the lower edge flange has a raised edge or lip surrounding the second aperture so as to form an annular groove between the lip and the inner edge of the upper aperture when the surfaces of the mating flanges and ledges are in contact and the apertures are coaxial. The two flange and ledge surfaces are normally welded or otherwise secured together. A sealing member is disposed in the annular groove so that a fluid seal is created between the flanges about the annular groove. This sealing connection overcomes a sealing problem in the bolt region that would otherwise typically be present in this region, and therefore extends the service life of the fluid tank.
Means of combining the joining of two tank halves with the attachment of the tank flange to the vehicle body frame can also be achieved by inserting a bolt through the flange apertures and into a corresponding aperture in the vehicle body. An elastic piece is placed between the edge flanges and the body of the vehicle, in order to protect the weld seam at the flange edges. The elastic piece may also serve as a vibration isolator.